Hi Al
Great looking build - congrats.
As you may already know the markings are for a tank of the 1 Krechowiecki Lancers - a pre-war unit reformed within the 2 Brygady Pancernej IIKP. The horses head denotes the regt and the shape of the surround (a circle in this case) denotes the squadron (triangle for first squadron, square of second etc). I suspect that the markings represent a vehicle being used when the II KP was in action in the Marche Region of Italy during 1944 - 46 (they remained as an occupying force). Famous actions included the pursuit to Bologna.
Whilst I don't have any photos of this particular vehicle, I now have stack of photos of similar in-theatre Polish vehicles (Sherman IIIs, Ics, Ic hybrids). Let me know if you need any detail shots.
The only thing I'd add to Roy's comments is that almost all photos of Polish armour in Italy show Shermans with regt fitted applique armour in the usual places. Track armour, over the front glacis, is also commonly seen in front-line use - the famous Leretto parade shows it but in a slightly tidied-up form.
Finally, the fig is sort of spot on. Polish tankers in Italy appear to have worn a mixture of light-weight coveralls, denims, or shirt sleave order (tropical not BD). The black beret would have been worn at all times - pushed back in a more continental style, rather than as per Kings regs, with the Polish Army Eagle to the right of the left eye. I'm not sure if any of the Hornet heads get this curious arrangement completly right.
I hope that's helpful. Keep up the great work.
Cheers
Karol